1. Field of Invention
The invention relates to an electrically operated vehicle drive controller and an electrically operated vehicle drive control method.
2. Description of Related Art
A vehicle drive unit is conventionally mounted to a hybrid vehicle, as an electrically operated vehicle, and is structured so as to transmit one portion of torque of an engine, i.e., engine torque to an electric generator (electric generator motor) and also transmit the remaining engine torque to a drive wheel. The vehicle drive unit has a planetary gear unit, as a differential rotating unit, having a sun gear, a ring gear and a carrier. The carrier and the engine are connected to each other. The ring gear and a drive motor and the drive wheel are connected to each other. The sun gear and the electric generator are connected to each other. Rotations outputted from the ring gear and the drive motor are transmitted to the drive wheel so that a driving force is generated.
In the vehicle drive unit, an inverter is arranged between the drive motor and a drive motor controller. The inverter is operated in accordance with a driving signal sent from the drive motor controller, and generates the electric currents of U, V, W phases by receiving a direct electric current from a battery, and supplies the electric current of each phase to the drive motor. Therefore, the inverter has a plurality of transistors, such as six transistors, as switching elements. A pair of transistors makes up a unit that forms a transistor module (IGBT) for each phase (U, V, W). Accordingly, when the driving signal is sent to each transistor in a predetermined pattern, the transistor is turned on and off and the electric current of each phase is generated.
The rotating speed of the drive motor, i.e., the drive motor rotating speed is detected by a drive motor rotating speed sensor. For example, the torque of the drive motor, i.e., the drive motor torque, etc. in the drive motor are controlled on the basis of the drive motor rotating speed.
Further, the rotating speed of the electric generator, i.e., the electric generator rotating speed is detected by an electric generator rotating speed sensor. The rotating speed of the engine as a target, i.e., an engine target rotating speed is limited by upper and lower limit values in accordance with the present vehicle speed such that no electric generator rotating speed becomes a predetermined value or more, e.g., see JP-A-2002-39008.